From: zhouchuyi <zhouchuyi@xxxxxxxxxxxxx>
When we successfully find a pageblock in
fast_find_migrateblock(), the block will be set
skip-flag through set_pageblock_skip().
However, when entering isolate_migratepages_block(),
the whole pageblock will be skipped due to the branch
'if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages))'.
Eventually we will goto isolate_abort and isolate nothing.
That cause fast_find_migrateblock useless.
In this Patch, when we find a suitable pageblock in
fast_find_migrateblock, we do noting but let
isolate_migratepages_block to set skip flag to
the pageblock after scan it. Normally, we would
isolate some pages from the fast-find block.
I use mmtest/thpscale-madvhugepage test it. Here
is the result:
baseline patch
Amean fault-both-1 1331.66 ( 0.00%) 1261.04 * 5.30%*
Amean fault-both-3 1383.95 ( 0.00%) 1191.69 * 13.89%*
Amean fault-both-5 1568.13 ( 0.00%) 1445.20 * 7.84%*
Amean fault-both-7 1819.62 ( 0.00%) 1555.13 * 14.54%*
Amean fault-both-12 1106.96 ( 0.00%) 1149.43 * -3.84%*
Amean fault-both-18 2196.93 ( 0.00%) 1875.77 * 14.62%*
Amean fault-both-24 2642.69 ( 0.00%) 2671.21 * -1.08%*
Amean fault-both-30 2901.89 ( 0.00%) 2857.32 * 1.54%*
Amean fault-both-32 3747.00 ( 0.00%) 3479.23 * 7.15%*
Fixs: 'commit 70b44595eafe9 ("mm, compaction: use free lists
to quickly locate a migration source")'
Signed-off-by: zhouchuyi <zhouchuyi@xxxxxxxxxxxxx>
---
mm/compaction.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 1f89b969c..a1a2b50c8 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1852,7 +1852,6 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
pfn = cc->zone->zone_start_pfn;
cc->fast_search_fail = 0;
found_block = true;
- set_pageblock_skip(freepage);
break;
}
}
--
2.20.1
